Return bend fitting for cracking coils



Nov. 14, 1933. H. c. STOCKHAM RETURN BEND FITTING FOR CRACKING GQILS Filed Jan. 25, 1933 4 Sheets-Sheet l 7 INVENTOR TORNEY Nov. 14, 1933. H. c. STOCKHAM ,9 5,

RETURN BEND FITTING FOR CRACKING COILS Filed Jan. 25, 1933 4 Sheets-Sheet 2 FIG. 4.

TTORNEY Nov. 14, 1933. H. c. STOCKHAM 1,935,233

RETURN BEND FITTING FOR CRACKING COILS Filed Jan. 25, 1933 43heets-Sheet a FIG. 8.

T I WEQM,

ATTORN EY 4 Sheets-Sheet 4 F 6. ll.

H. c. STOCKHAM RETURN BEND FITTING FOR CRACKING COILS Filed Jan. 25, 1935 FIG. /2.

Nov. 14,, 1933'.

INVENTOR 9 a B WORNEY Patented Nov. 14, 1933 RETURN BEND FITTING FOR CRACKING COILS Herbert C. Stockham, Birmingham, Ala., assignor to Fred C. Fantz, Webster Groves, Mo.

Application January 25, 1933. Serial No. 653,368

4 Claims.

My invention relates more particularly to that type of fitting which is designed to connect adjacent tubes in the cracking coil or tube bank in the refinery.

It is well known in the industry that it is most desirable to provide quick and convenient access to the interior of the tubes for the purpose of I removing the coke which is deposited on the interior during the cracking operations. This accumulation of coke is very dangerous due to the fact that it acts as an insulation and prevents the transmission of the heat to the oil, and as a consequence there is danger of the tube being heated beyond its strength and thus produce a ruptured tube with attendant property damage and possible loss of life.

It is also well known that tubes warp seriously during the cracking operation, and it is desirable to be able to turn the tubes over when they sag or warp, thus increasing the life of equipment.

A further feature which has been found to be most desirable is the ability to remove a tube to a less hazardous position, so that the length of the life of the equipment can be materially lengthened. None of these desirable features can be attained by means of the well known rolled in type of header or junction box in which the tube is expanded or rolled into the header or housing and thereby permanently attached to it, making it impossible to remove the tubes without cutting them off from the header box and the ends of the tubes then have to be shipped out of the housing, or burned out with an acetylene torch. As a consequence, there is a growing tendency in the industry to provide demountable tubes, which are usually formed by means of upset or shouldered portions on the ends of the tubes, which are engaged by collars or bushings and toggles with set screws are mounted in the housing which force the return bend into a tight engagement with the ends of the tubes.

My invention has for its object to provide a construction which can be quickly and easily assembled, and which will entirely eliminate the necessity for a sectional metal ring or bushing intermediate the walls of the housing and the shoulders on the tubes.

My means of accomplishing the foregoing objects may be more readily understood by having reference to the accompanying drawings, which are hereunto annexed and are a part of this specification, in which Fig. l is a side elevation of my device partly in section to show the means of mounting the tubes on the inside;

Fig. 2 is a plan view of the same, part of the housing and U or return bend being omitted;

Fig. 3 is a section on the line 3-3 in Fig. 1;

Figs. 4, 5, 6 and '7 are detail views of my device;

Fig. 8 is a side elevation partly in section of the modified form of my device;

Fig. 9 is a plan view of the same, the housing, U bend and tubes being omitted;

Fig. 10 is a section on the line 1010 of Fig. 8;

Fig. 11 is a view of one section of the housing, the bottom being broken away to show the interior construction; and

Fig. 12 is a side elevation of Fig. 9.

Similar reference numerals refer to similar parts throughout the entire description.

As shown in the drawings, I have illustrated a conventional return or U bend 1 which is adapted to connect with still tubes 2 and 3. The ends of these tubes are offset to form shoulders 4.

As illustrated, the face of the return bend is provided with an annular groove adapted to receive the ends of the still tubes 2 and 3, but it will be apparent to persons skilled in the art that my invention is not confined to any particular type of joints for the connection between the return bend and the tubes and any type of joint may be employed without departing from my invention.

The return bend 1 is mounted in a housing comprised of five parts. As each half is identical, I shall only describe one half as it will be well understood when the description is completed that the other half is precisely the same and consequently there would be no necessity of duplication of the description. These five parts of the housing comprise two members having annular portions 5 and upwardly extending side walls 6 and '7 on the annular portions. In the upper part of these side walls I mount toggles 8 which carry set screws 9, the inner ends 10 of which are adapted to engage abutments 11 formed on the external walls of the return bend l.

The annular portions 5 are provided with internal threads 6 which are adapted to engage threads formed on the remaining portion of the housing which consists of a plate 12 which is provided with two upwardly extending semicylindrical portions 13 and 14 which are adapted to encircle the ends of the tubes and are provided with internal shoulders which engage the shoulders formed by the upset portions of the tubes. The outside halves of the tubes are encircled by two separate semi-circular ends 15 and 16 which are also provided with upwardly extend- 2 aaaasa ing semi-cylindrical portions 17 and 18. The parts of this bottom plate comprising sections 12, 15 and 16 are held together by screwing the annular portions 5 over them so as to hold them securely in position.

It will be obvious from the foregoing description that when the annular portions 5 are screwed down in place that the complete housing will be held as if it were solid. The return bend can then be placed upon the ends of the tubes, the toggles 8 inserted into position and the set screws 9 tightened and a tight joint will be formed between the ends of the tubes and the face of the return bend 1.

In Figs. 8 to 12, I have shown a modified form of construction for this device. In this form of construction I provide means to hold the tubes in alignment at all times by making a plate 20 which is provided with upwardly extending semicylindrical portions 21 and 22 adjacent each end. The plate 20 has a central'recess 23 in which I mount two blocks each having separate semicircular rings 24 and 25 which are adapted to encircle the inner halves of the tubes. It will be apparent that when this type of construction is employed the tubes will be held correctly in alignment when the U bend 1 is removed, for the purpose of removing coke from the interior of the tubes and can be replaced with ease and a tight joint always assured.

In this construction, as in that heretofore described, the annular portions 5 are screwed on to the upwardly extended bending threaded portions and in this manner they are held securely together when the housing is decidedly as if it were made of one piece. At the same time it will be apparent that the tubes are demountable and can be quickly and easily removed by disassembling the housing which may be conveniently accomplished by unscrewingthe annular portions 5 from the upwardly extending threaded portions of the plate and blocks, when the separate blocks may be removed and the tubes can be withdrawn. It will probably be found desirable to make the openings in the plates eccentric so as to facilitate the insertion of the upset portion of the tubes.

Having described my invention what I regard as new and desire to secure by Letters Patent is:

1. In a refinery apparatus, a conventional return bend adapted to connect a pair of still tubes to provide a passageway therethrough, a com pound housing comprising two members having annular portions and upwardly extending side walls, a plate having upwardly extending semi circular portions provided with external threads,

two separate blocks each of which has corre-- sponding semi-circular threaded portions, internal shoulders in said threaded portions which engage the shoulders on said tube, internal threads in said annular portionswhich fit the threads on the semi-circular portions and means mdunted in said side walls to draw the return berid and tubes into a tight joint.

2. In a refinery apparatus, a conventional return bend adapted to connect a pair of still tubes toprovide a passageway therethrough, a compound housing comprising two members having annular portions and upwardly extending side walls, a bottom plate having upwardly extending semi-circular' portions provided with external threads, two separate blocks each of which has corresponding semi-circular threaded portions, internal shoulders in said threaded portions which engage the shoulders on said tubes, internal threads in said annular portions which fit the threads on the semi-circular portions and means mounted in said side walls to draw the return bend and tubes into a tight joint.

3. In a refinery apparatus, a conventional return bend adapted to connect a pair of still tubes to provide a passageway therethrough, a compound housing comprising two members having annular portions and upwardly extending side walls, a plate having'upwardly extending semicircular portions provided with external threads, adapted to partially encircle the outer half of the tubes, two separate blocks each of which has corresponding semi-circular threaded portions, internal shoulders in said threaded portions which engage the shoulders on said tubes, internal threads in said annular portions which fit the threads on the semi-circular portions adapted to encircle the inner halves of the tubes.

4. In a refinery apparatus, a conventional return bend adapted to connect a pair of still tubes to provide a passageway therethrough, a compound housingcomprising two members having annular portions and upwardly extending side walls, a plate having upwardly extending semicircular portions provided with external threads, adapted to partially encircle the inner halves of the tubes, two separate blocks each of which has corresponding semi-circular threaded portions, internal shoulders in said threaded portions which engage the shoulders on said tubes, internal threads in said annular portions which fit the threads on the semi-circular portions adapted to encircle the outer halves of the tubes.

HERBERT C. STOCKHAM. 

